class Solution:
    def isInterleave(self, s1: str, s2: str, s3: str) -> bool:

        length1 = len(s1)
        length2 = len(s2)
        if length1 + length2 != len(s3):
            return False
        dp = [[False for _ in range(length2 + 1)] for _ in range(length1 + 1)]
        dp[0][0] = True
        for i in range(1, length1 + 1):
            dp[i][0] = dp[i - 1][0] and s1[i - 1] == s3[i - 1]
        for j in range(1, length2 + 1):
            dp[0][j] = dp[0][j - 1] and s2[j - 1] == s3[j - 1]
        for i in range(1, length1 + 1):
            for j in range(1, length2 + 1):
                dp[i][j] = (dp[i - 1][j] and s1[i - 1] == s3[i + j - 1]) or \
                           (dp[i][j - 1] and s2[j - 1] == s3[i + j - 1])

        return dp[length1][length2]


if __name__ == '__main__':
    s = Solution()
    r = s.isInterleave("ab", "bc", "bbac")
    print(r)
